//暴露一个方法
exports.sayHi1 = function () {
    document.write("<h1>狂神说前端</h1>");
};
exports.sayHi2 = function () {
    document.write("<h1>狂神说JAVA</h1>");
};
exports.sayHi3 = function () {
    document.write("<h1>狂神说Linux</h1>");
};
exports.sayHi4 = function () {
    document.write("<h1>狂神说Windows</h1>");
};